Internal combustion engine exhaust gases may require after treatment to control emissions. An oxidation catalyst (OC) device may reduce carbon monoxide (CO) and unburned hydrocarbon (HC). A selective catalyst reduction (SCR) device may reduce NOx (a generic term for mono-nitrogen oxides NO (nitric oxide) and NO2 (nitrogen dioxide)), and a particulate filter (PF) may reduce carbon and other particles in the exhaust gases. Both OC and SCR devices require an activation, or light-off, minimum temperature for operation. Higher temperature engine operation may help raise the OC and SCR temperatures to the minimum operation temperatures at the expense of fuel consumption. Electrical heating, by an electrically heated catalyst (EHC) device, may provide localized temperature benefits without excess fuel consumption. Electrical heating capacity may be limited by the operational limits of electrical supply components.